Require FLAG_WRITE when FLAG_CREATE_ALWAYS is specified

base/files/file_posix.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 165 matching lines @@
   DCHECK(!IsValid());
 
   int open_flags = 0;
   if (flags & FLAG_CREATE)
     open_flags = O_CREAT | O_EXCL;
 
   created_ = false;
 
   if (flags & FLAG_CREATE_ALWAYS) {
     DCHECK(!open_flags);
+    DCHECK(flags & FLAG_WRITE);

[rvargas (doing something else), 2014/06/05 19:27:52]

We should keep the behavior consistent across platforms... so the Windows
implementation should do the same thing.

[mdempsky, 2014/06/09 17:56:22]

Done.

     open_flags = O_CREAT | O_TRUNC;
   }
 
   if (flags & FLAG_OPEN_TRUNCATED) {
     DCHECK(!open_flags);
     DCHECK(flags & FLAG_WRITE);
     open_flags = O_TRUNC;
   }
 
   if (!open_flags && !(flags & FLAG_OPEN) && !(flags & FLAG_OPEN_ALWAYS)) {
@@ skipping 282 matching lines @@
       return FILE_ERROR_FAILED;
   }
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   DCHECK(!file_.is_valid());
   file_.reset(file);
 }
 
 }  // namespace base